Encrypted message, if message is destroyed without being decrypted new instance created. If decrypted person who reads the message becomes obsessed with encrypting it with the best available methods. When reencrypted the original encrypted instance can be destroyed.

So there would be several instances of the message as sometimes the re-encryption is not finished before the person who decrypted it died.

When subjects are asked why they are obsessed with encrypting the message with as strong an encryption as possible subjects will tell of serious problems if it becomes widespread. While generally they will be quite vague on this sometimes they will mention specific consequences, up to and including XK events. However it appears that this is done to get access to better encryption resources and allow the subject more time to encrypt the message.

Nobody who has read the messages has ever allowed or encouraged anyone else to read it. Senior staff who have read the message have devoted enormous resources to encrypting it in the stongest ways possible. Thousands of man-hours have been wasted learning dead languages merely to translate it into those pastiches of those languages that would be hard to understand without knowledge of several of them. Supercomputers have been dedicated to the task sometimes for days at a time.

I moved your thread description to the first post and trimmed it above, OP, since it was taking up a lot of space on the forum listing. Try to keep thread descriptions under 7 lines so you don't visually crowd out other people's threads. ~Zyn

So you know, the "it makes you crazy until you do dangerous/silly/expensive/dumb stuff" approach isn't particularly interesting on its own anymore, given how many times SCPs with that effect have been written. Take a look at the articles tagged with "compulsion". Furthermore, the SCP's effect forcing someone to do something tends to be a bit of a lame narrative, since things are more interesting if there's a struggle involved, and/or if the people instead do terrible things of their own volition. Consider reading through the further discussion on the narrative issues of compulsion and addiction effects.

Why does the encrypted message exist? Did it have a purpose? What if someone with no cryptography experience whatsoever was exposed to it?

Also, I have trouble believing that the Foundation allowed staff to waste "thousands of man-hours" on this thing instead of amnestics-wiping their memories of the thing and putting them back to work on their usual jobs.